This invention relates to an apparatus for forming packages from a wrapper hose. The hose in which groups of flat articles to be packaged are uniformly spaced, is advanced to welding shoes which seal the hose by providing transverse seams between the groups. On both sides of the hose there are arranged circulating endless chains to which there are secured pairs of pressing fingers which pinch the hose between two article groups and which laterally support the hose during its motion in engagement with the welding shoes. The purpose of the chains equipped with the pressing fingers is to prevent the leading or trailing items of one item group from falling on their face within the hose; such an occurrence would lead to an interruption of the operation. Despite this known arrangement, such malfunctions occur in apparatuses constructed according to the prior art: sometimes the trailing items of a group fall shortly before the hose is grasped by the welding shoes behind such item.